1. Field of the Invention
The present invention relates in general to a deck mechanism of a magnetic recording and reproducing apparatus, such as a slide loading type camera recorder, and more particularly to a tape running system for such a deck mechanism of the magnetic recording and reproducing apparatus.
2. Description of the Prior Art
Conventionally, a slide loading type camera recorder, so to speak a slide loading type camcorder, comprises a slide base which is mounted on a stationary base plate such that it reciprocates frontwards and backwards. A rotary head drum is slantingly mounted on the stationary base plate while both a supply reel table and a take-up reel table are mounted on the slide base. The conventional slide loading type camcorder further includes an operable cassette housing hinged to a side of the stationary base plate by means of a hinge shaft. In order to load a tape cassette in the deck mechanism of the camcorder, the tape cassette is inserted into the cassette housing in an eject position and turned downwards about the hinge shaft along with the cassette housing. At this state, the slide base moves backwards, that is, in the direction toward the rotary head drum, thereby achieving the loaded state of the cassette tape.
In the above slide loading type camcorder, a loading lever mechanism comprising a plurality of link levers is operated in cooperation with a pair of loading gears, mounted on the stationary base plate such that they engage with each other. Hence, the loading lever mechanism moves a slant post assembly to its play mode position. At this time, the slide base is moved to its play mode position by an auxiliary drive power transmission unit.
As described above, the conventional slide loading type camcorder should drive the slant post assembly and the slide base employing individual drive units, thereby increasing in the number of required elements, resulting in increase of manufacturing cost. In addition, the requirement of varieties of elements complicates the construction of the camcorder and prohibits the achievement of the recent trend toward compactness and lightweight designs.
On the other hand, in the case of a conventional portable video cassette recorder (VCR) of the VHS type which is more generalized than the aforementioned portable camcorder, it is well noted that the designing condition for the rotary head drum and the slant post, both elements being regarded as kernel elements of the tape running system of the VCR, have a large effect upon the tape running performance of the VCR. Otherwise stated, the designing condition, such as a slant direction and a slant angle of the rotary head drum, a lapping angle of the tape with respect to the rotary head drum and a lapping angle of the tape with respect to the slant post has a large effect upon the tape running performance of the VCR of the VHS type. In this regard, the above designing condition has been regarded as an important factor in the determination of the tape recording and playback performance of the VCR.
However, in the case of the conventional slide loading type camcorder, there is a problem in that the above designing condition for the rotary head drum and the slant post is not suitable for shortening of the Y-directional length of the result camcorder as well as for reduction of the tape running load.
Moreover, as is well known to those skilled in the art, the conventional camcorder is provided with an automatic tension control unit for automatically controlling the tensile force of the tape. Thus, the tensile force of the tape, otherwise stated, the tensile force imparted to the tape in a tape running mode, such as a playback mode, is intended to be constantly maintained at, a predetermined level. However, in the conventional camcorder, the tensile force imparted to the tape in both the playback mode and a stop mode is fixed, so that there is a problem in that the rotary head drum is not smoothly operated due to the tensile force of the tape when the rotary head drum, stopped in the stop mode, starts to be rotated in the playback mode. The above problem becomes worse in the case of a dewed state of the inside of the camcorder even when the dew level of the inside of the camcorder is relatively low such that it is not detected by a dew sensor.
In order to overcome the above problem caused by the tensile force of the tape, there has been proposed a device for smoothly starting the rotary head drum by making the tensile force of the tape in the stop mode be maintained at a predetermined level lower than that in the playback mode. However, a problem of this device is resided in that it should include a complicated turning mechanism for turning a tension arm having a tension post and which inefficiently consumes a large quantity of driving power for driving the complicate turning mechanism.